Peter Cassells found higher education needs an extra one billion euro over the next 15 years, including 600 million euro by 2021 just to make up for the cuts imposed during the recession.

And he said the numbers going to university and college are going to increase by a third and that the financial black holes in the sector are hitting the Institutes of Technology hardest.

Annie Hoey, president of the Union of Students in Ireland, said there was a concern that political will would determine whether loans are forced on to students.

"It needs to made clear that this is a matter of political will - the fact there are three options," she said.

"If a loan system is brought in it will be because a government is choosing that option.

"They will be choosing to put a mortgage on young people for their education."

She added: " Publicly-funded free education is not impossible. If it was, so many other countries in Europe wouldn't offer it."

Under a proposed student loan system, third level education would be provided free for all but those who graduate and go on to earn more than a set threshold would then pay for their course.

Education Minister Richard Bruton said more funding for colleges and universities would have to be matched by improvements in the system.

He highlighted the need for 50,000 retraining places over the next five years and a 7% increase in enrolment for people from the most disadvantaged socio economic groups.

He also said part-time study should increase by 25%.

"Over recent years, the higher education sector responded well to massively increased student numbers in the context of tightened budgets," Mr Bruton said.

"This has been a great achievement but is not sustainable, and we are now starting to see difficulties emerge in achieving public policy goals in areas like skills and disadvantage."

Tom Boland, chief executive of the Higher Education Authority, said: " There can be no question that urgent intervention is required to address a rapidly deteriorating financial situation across all of our institutions.

"This poses an immediate risk to their ability to maintain high quality provision and to meet the continuing growth of student demand which, as the report makes clear, will place significant pressure on the sector over the next 15 years."

Ned Costello, chief executive of the Irish Universities Association, said the report clearly illustrates the crisis in higher education funding.

"An immediate infusion of funds is needed: firstly just to ensure viability and secondly to begin to return our exceptionally high student staff ratios to normal levels," he said.

The Anti Austerity Alliance said the three options have created a huge problem for the Government and Fianna Fail and called for a new, bigger student movement to fight fees.

Ruth Coppinger TD said: " The introduction of a student loan model will put students off going to college. The prospect of having huge amounts of debt around their necks will put many from disadvantaged or working class backgrounds off."